I have a blood orange tree in my back yard and my suggestion would be to juice them, including as much of the pulp as possible, and freeze it. I don't have that recipe in hand but I did read it a couple years ago and I seem to recall it requires sections of fruit to be boiled or something. I've never tried to freeze sections of fruit, but it may work. I know freezing juice works well.
I think you would lose much of the flavor and aromatics by dehydrating the zest so I would use fresh zest from some other type of orange. There's no difference, really. I also have valencia orange and tangelo trees and I can't tell a difference between the taste and aromatics of the zest. Color, maybe, but I assume the zest will be filtered out. Plus, you'll get all the color and flavor you need from the juice. Good luck.
